Referring to FIG. 1, depicting a conventional radio-frequency (RF) transceiver front-end circuit 500 includes an antenna 50, a power amplifier 51, a low-noise amplifier 52, a first λ/4 transmission line 53, a second λ/4 transmission line 54, a first switch 55 and a second switch 56. The antenna 50 is individually connected to the first λ/4 transmission line 53 and the second λ/4 transmission line 54. The first λ/4 transmission line 53 is further connected to the power amplifier 51, and the second λ/4 transmission line 54 is further connected dot the low-noise amplifier 52. The first switch 55 is connected to the first λ/4 transmission line 53 and the power amplifier 51, and the second switch 56 is connected to the second λ/4 transmission line 54 and the low-noise amplifier 52.
As such, the conventional RF transceiver front-end circuit 500 is capable of receiving and transmitting signals through controlling the first switch 55 and the second switch 56. However, because the above conventional structure is required to transmit signals through the first λ/4 transmission line 53 and the second λ/4 transmission line 54, the RF transceiver front-end circuit 500, when designed as an integrated circuit, is limited by the volume of the first λ/4 transmission line 53 and the second λ/4 transmission line 54 and fails to be effectively miniaturized.
Further, the signal transmission process of the first λ/4 transmission line 53 and the second λ/4 transmission line 54 inevitably produces loss that disfavors applications. For example, assuming that the power amplifier 51 intends to boost the power for transmitting a signal to 0.1 W, the power is however dropped to 0.08 W when the signal is transmitted to the antenna 50 through the first λ/4 transmission line 53. Such power drop compromises the purpose of providing the power amplifier 51, and the power drop in the signal also affects whether a receiving end can reliably and stably receive the signal.